Yeah, I don't know if I like the sound of this either. But we haven't heard everything yet though.

Let's say it's just an auctionhouse with auctions by NPCs that you can bid/buyout on, isn't that just a messed up vendor? Instead of buying an item for X gold, you can bid on it and maybe win it for Y or Z gold. Sounds wierd. Sounds like there's more to this that we don't know.

Yes that was my first notion as well.

The only analogue I could think of was the limited supply vendors...
(you know these vendors that sell only x patterns or items and if someone else bought it you had to camp it until the item re-spawned)

But it seems like an awful lot of trouble to go to just to make limited supply vendors centralized.

Hence my suspicion that they're making ready to install gear for gold in the game.
Initially game gold only but the infrastructure would be there and players conditioned to making this kind of transaction with NPCs for them to "enable you to use your Battle.net balance" to make purchases down the road.